1. Field of the Invention
This invention relates to an IL-4 mutein receptor antagonist coupled to a non-protein polymer such as polyethylene glycol. In addition, related formulations, dosages 15 and methods of administration thereof for therapeutic purposes are provided. These modified IL-4 mutein receptor antagonists, and associated compositions and methods are useful in providing a treatment option for individuals afflicted with severe asthma, chronic obstructive pulmonary disease, and related lung conditions.
2. Background Information
Asthma is characterized by variable, reversible airflow obstruction, and airway hyperresponsiveness (AHR), associated with an infiltration of the bronchial mucosa with activated T-lymphocytes (T-cells), and eosinophils. These cells, along with resident airway mast cells, secrete a variety of cytokines and mediators that play a fundamental role in the pathogenesis of the disease. CD4+ Th2 cells, through the release of specific cytokines (IL-4, IL-5, IL-9, and IL-13), are thought to orchestrate the disease process (1,2). In particular, the Th2 cytokines IL-4, and IL-13, are considered pivotal to the development and maintenance of airway inflammation and airway hyperresponsiveness.
A number of in vivo studies also support the pivotal role of IL-4 and IL-13 in the pathogenesis of asthma. Using animals deficient in either cytokine, or reagents that neutralize either IL-4 or IL-13 function, an important role of these cytokines is observed in regulating the primary and secondary immune response leading to airway inflammation and airway hyperresponsiveness (3, 4). Cumulatively, these data suggest that IL-4 and IL-13 may play both overlapping and independent roles in the allergic airways response, and that targeting both cytokines could have significant added benefit to targeting either cytokine alone.
Antagonists of IL-4 have been reported in the literature. Mutants of IL-4 that function as antagonists include the IL-4 antagonist mutein IL-4/Y124D (Kruse, N., et al., Conversion of human interleukin-4 into a high affinity antagonist by a single amino acid replacement, Embo J. 11:3237-44, 1992) and a double mutein IL-4-[R121D/Y124D] (Tony, H., et al., Design of Human Interleukin-4 Antagonists in Inhibiting Interleukin-4-dependent and Interleukin-13-dependent responses in T-cells and B-cells with high efficiency, Eur. J. Biochem. 225:659-664 (1994)). The single mutein is a substitution of tyrosine by aspartic acid at position 124 in the D-helix. The double mutein is a substitution of Arginine by Aspartic Acid at position 121, and of tyrosine by aspartic acid at position 124 in the D-helix. Variations in this section of the D helix positively correlate with changes in interactions at the second binding region.
Mutant variants of IL-4 demonstrating agonism or antagonism of wild-type IL-4 may be useful for treating conditions associated with one of the pleiotropic effects of IL-4. For instance, antagonists of IL-4 would be useful in treating conditions exacerbated by IL-4 production such as asthma, allergy, or other inflammatory response-related conditions. Agonists of IL-4 may be useful for treating conditions wherein the presence of IL-4 is associated with the amelioration or attenuation of a disease, for example, an autoimmune disease such as Rheumatoid Arthritis, Multiple Sclerosis, Insulin-dependent Diabetes Mellitus, etc. These autoimmune diseases are characterized by a polarization in production of the T helper cell populations, types 1 and 2 (Th1, Th2). Naive CD4+ T cells differentiate into Th1 or Th2 subsets, depending on the cytokine present during stimulation. An IL-4 agonist would ideally shift production to the T-helper cell desired, i.e., towards Th2, thereby having a therapeutic effect.
PCT/US93/03613 discloses an IL-4 variant having a Phe-Leu or Tyr-Leu sequence in a alpha-helical domain and a negatively-charged amino acid within two amino acids immediately upstream or downstream from the Phe-Leu or Tyr-Leu sequence, the variant having an increased affinity for the IL-4 receptor by virtue of a neutral amino acid substituted for the negatively-charged amino acid. It also discloses that the specific substitution of Trp-Leu or Phe-Leu within an a-helix of IL-4 within 2-residues of a negatively charged residue results in improved affinity. The variant is an IL-4 fusion protein (with diphtheria toxin).
A recombinant mutein protein (IL-4RA) derived from human IL-4 mutated in two positions of its amino acid sequence was previously reported in U.S. Pat. Nos. 6,028,176 and 6,313,272. IL-4RA binds with high affinity to the human IL-4 receptor alpha chain, an important functional signaling component of both the IL-4 and IL-13 receptor complexes. This mutein has no agonist activity, and acts as a potent competitive IL-4 and IL-13 receptor antagonist in vitro (See U.S. Pat. Nos. 6,028,176 and 6,313,272). A significant drawback to the use of IL-4RA is its relatively short half life in vivo (approximately 3-6 hrs). Pharmacokinetic/pharmacodynamic modeling of IL-4RA in the primate asthma model indicates that the effective average steady state concentration for optimal therapeutic effect is approximately 60 ng/ml.
One approach to overcoming the short half life is frequent administration of the IL-4RA mutein to a patient, however frequent administration (usually by injection or tracheal intubation) creates very significant barriers to patient acceptance of the therapy and therapeutic administration in a clinic.